Apparatus and method for shucking oysters

ABSTRACT

THIS INVENTION PERTAINS TO SHUCKING FRESH BIVALVES AND IT COMPASSES BOTH AN APPARATUS AND METHOD WHICH REMOVES RAPIDLY, AND WITHOUT DAMAGE, THE EDIBLE PORTION OF THE BIVALVE. THE INVENTION CONSISTS OF REMOVING A PORTION OF THE SHELLS OF THE BIVALVE (PREFERABLY AFTER SOME OF THE FLUIDS CONTAINED IN THE BIVABLE CAVITY HAVE BEEN ELIMINATED PARTICULARLY IN THE CASE OF OYSTERS), THEREAFTER SEVERING MUSCLES OF THE BIVALVE WHICH CONNECT THE MEAT TO THE SHELLS, AND FINALLY SEPARATING THE MEAT AND THE SHELLS, AND THE APPARATUS FOR ACCOMPLISHING THE FOREGOING OPERATION. THE INVENTION PERTAINS TO BIVABLES IN GENERAL BUT IS ESPECIALLY USEFUL IN THE SHUCKING OF OYSTERS AND CLAIMS.

Sept. 20, 1971 s. e. HARRIS ETAL 3,605,180

APPARATUS AND METHOD FOR SHUCKING OYSTERS Filed Sept. 30, 1968 7Sheets-Sheet 2 56. 3a F/a 35 uuuu I 4: L i //V VENT 0E5,

STEzL/NG 6 Maze/5 14 55 P. 2055a 15 Sept. 20, 1971 s. G.HARRIS ETALAPPARATUS AND METHOD FOR SHUCKING OYSTERS Filed Sept. 30, 1968 7Sheets-Sheet 3 F nw n BEA/P 2059a Sept. 20, 1971 s. e. HARRIS ETALAPPARATUS AND METHOD FOR SHUCKING OYSTERS Filed Sept. 50, 1968 7Sheets-Sheet 4.

S. G. HARRIS ETAL APPARATUS AND METHOD FOR SHUCKING OYSTERS Sept. 20,1971 7 Sheets-Sheet 5 Filed Sept. 30, 1968 E Z a M k Mm we mm 2 Sept.20, 1971 s. e. HARRIS ETTAL APPARATUS AND METHOD FOR snucmue OYSTEHSFiled Sept. 30, 1968 7 Sheets-Sheet 6 2 W; Z 62 e y J5 United StatesPatent "ice 3,605,180 APPARATUS AND METHOD FOR SHUCKING OYSTERS SterlingG. Harris, Beaufort, and Ben P. Zober, Charleston, S.C., assignors toHarris Automated Machinery C0,, Dover, Del.

Filed Sept. 30, 1968, Ser. No. 763,816 Int. Cl. A22c 29/00 US. CI. 17-7419 Claims ABSTRACT OF THE DISCLOSURE This invention pertains to shuckingfresh bivalves and it encompasses both an apparatus and method whichremoves rapidly, and without damage, the edible portion of the bivalve.The invention consists of removing a portion of the shells of thebivalve (preferably after some of the fluids contained in the bivablecavity have been eliminated particularly in the case of oysters),thereafter severing muscles of the bivalve which connect the meat to theshells, and finally separating the meat and the shells, and theapparatus for accomplishing the foregoing operation. The inventionpertains to bivables in general but is especially useful in the shuckingof oysters and clams.

BACKGROUND OF THE INVENTION (1) Field of the invention Despite thecontinuous efforts from early times to devise a mechanical method forshucking bivalves, particularly oysters and clams, shucking by handcontinues to be the only commercially feasible means for removing in theuncooked fresh condition the meat from these particular mollusks. Theproblem of shucking bivalves is steadily becoming more acute with thegrowing storage of skilled shuckers and the steady rise in their wages.The absence of and great need for a good mechanical shucker has beenpublicized by the United States Department of Interior and by theMaryland Chesapeake Bay Affairs Commision; the revival of the nowdeclining oyster and clam industries along the Atlantic, Gulf, andPacific Coasts of the United States has been declared to depend upon thedevelopment of such a shucker. This long-felt need is recognizedthroughout the industry.

(2) Description of the prior art The prior art teaches the limitedopening of bivalves by electric shock, by microelectronic waves, byheating or freezing, by the use of chemical compounds, bycounterrotation of the upper and lower portion of portions of the oysterand clam shells, by cutting, grinding, or chipping the shells tofacilitate insertion of the shuckers knife. See US. Pats. Nos. 848,608;10,810; 3,206,796; 2,000, 075; 2,473,609; 3,239,877; 3,013,884 and3,070,834. However, as stated, the problem of shucking (both open ingand cutting the meat free from the shells) by mechanical means remainedunsolved prior to the present invention.

SUMMARY OF THE INVENTION The present invention is carefully adapted tocope with and exploit details of the physical characteristics ofbivalves, particularly oysters and clams, and for the first time toemploy an apparatus and method tailored to take advantage of some of thenatural features of bivalves which have long been ignored. As stated, abivalve when subjected to shock or trauma will open slightly. See HarrisPatent No. 2,832,989. Heretofore, the object of such shock has been tobring about a sufficient parting between the upper and lower shells tofacilitate the entry Patented Sept. 20, 1971 of a knife to free the meator to accelerate cooking of the meat.

As one of its features, the present invention utilizes, in the case ofoysters, the loss of fluid, commonly referred to as shell liquor, whichinvariably accompanies the shocked-induced partial opening of theshells. This fluid consists of the indigenous water and the products ofoyster metabolism which is entrapped between the body cavity of theshells and the meat when the shellfish is caught and removed from itshabitat. The meat of the bivalves is suspended 'by flotation in thisentrapped fluid.

After the shell liquor, which is sealed between the shells of the closedbivalve, is partly or entirely eliminated, a corresponding volume offree or air space is created. Gravity then causes the flesh of thebivalve to sag into the lowermost portion of the shell cavity, leaving avoid or air space in any portion of the bivalve cavity which is helduppermost. By utilizing this principle, and by holding uppermost theportion of the shells which one selects for removal, a substantiallygreater portion of the shells may be cut away without cutting ordamaging the meat than would otherwise be possible if the fluid had notfirst been removed from the cavity of the bivalve.

The invention also utilizes the fact that the adductor muscles ofbivalves of each species are always attached to particular areas of theshells. The invention so positions the bivalve as to (a) permit a largeincision to be made in the shells without cutting the meat, and (b)provide an unobstructed path of access to the adductor muscles for theknives which enter through the aperture so formed to sever thesemuscles. Another feature of the invention is the use of knives which inshape and operation are uniquely designed to follow the contour of theinterior surfaces of shells and to cut the muscles at the precise pointsof their attachment to the shells. A knife assembly based on apantograph movement for use on bivalves having especially irregulatorinterior shell contours is a further feature of the invention.

Broadly described, the inventive concept covers the method of holdingthe bivalve in a selected position with the portion of its shells whichare to be removed uppermost, removing the uppermost portions of the twoshells, widening the opening so created, cutting the ends of theadductor muscle by instruments which enter through the widened opening,and separating and collecting the meat and the shells. With respect tooysters and clams, some of the fluid is removed from the cavity as apreliminary operation in the preferred embodiment. The invention alsoextends to means for accomplishing the foregoing steps. With theexception of positioning the bivalves in the carriage and clampassembly, all of the operations are accomplished mechanically. Theinvention is carried out in four steps or at four stations which follow:

(1) The initial placement and subsequent holding of the bivalve in aselected position during the entire shucking operation.

(2) The making of a suitable opening in the shells of the bivalve byremoval of portions thereof.

(3) The enlargement of the opening by spreading (unnecessary in largeoysters and clams), the cutting of the adductor muscles, and theseparation of the edible portion of the bivalve from its shell.

(4) The release of the empty shells from the apparatus at a selectedlocation.

For simplicity, the apparatus which will hereinafter be described as thepreferred embodiment is a hand operated machine with the four stationsarranged along a straight horizontal conveyor track. Any other wellknownmechanical movement whereby the successive steps which comprise theinvention are performed may also be employed in practicing theinvention. For example, highly successful results have been obtained bythe use of a Geneva mechanism having the same four basic stationsactivated penumatically and an illustration of such a machine is shownin FIG. 19. The invention is not, therefore, restricted to anyparticular mechanisms by which the bivalve is moved from one station toanother, but extends to any mechanism which may be employed to carry outthe steps which are disclosed herein.

Since the method and apparatus which comprises the invention, mechanizethe shucking of bivalves, the in- 'vention is useful in any operationwherein bivalves have heretofore been shucked only by hand. For example,it is suitable for use in raw bars and especially in sea food packinghouses which shuck and package large volumes of fresh or subsequentlyfrozen bivalves for consumption at other locations. While the mainadvantage of the invention is the economy of mechanical over handshucking, a bivalve which is processed according to the invention is atleast comparable in quality to the best result achieved by handshucking. A significant portion of hand opened bivalves is mutilatedbecause of the lack of skill of many of the shuckers who are employed byseafood houses, and this factor detracts from quality, value andmarketability. By practicing this invention the adductor muscles aresevered very close to the shells to which they are attached insuringrecovery of all of the meat without damage.

The invention is also adaptable for the mechanical preparation ofoysters and clams on the half shell.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation.

FIG. 2 is a plan view.

FIG. 3a-g shows the sequence of operations.

FIG. 4 is a perspective of portion of machine at Sta. 3.

FIG. 5 is a front elevation of portion of machine at Sta. 3, withspreader movement in down position.

FIG. 6, front elevation of portion of machine at Sta. 3 with knivesextended to position of cutting muscle.

FIG. 7, knife blades enlarged.

FIG. 8, front elevation of Sta. 1.

FIG. 9, enlarged perspective of one holding clamp.

FIG. 10, fragmentary view of knife blade.

FIG. 11, cross-section of pantograph knife mechanism.

FIG. '12, section taken through line 1212 on FIG. 8.

FIG. 13, section taken on line 13-13 on FIG. 12.

FIG. 14, typical oyster showing top and bottom shells.

FIG. '15, oyster opened.

FIG. 16, typical oyster showing two positions of meat before and aftershocking.

FIG. 17, section taken through line 17--17 of FIG. 16.

FIG. 18, clam shells opened showing diamond blade out line prior toremoval of meat.

FIG. 19, invention as carried out by pneumatically activated Genevamechanism.

GENERAL DESCRIPTION FIGS. 1 and 2 show the front elevation and planview, respectively, of an interrelated series of four principalmechanisms which constitute the invention and the means by which theprocess disclosed is practiced. Referring to FIG. 1, the machine issupported by a table-like floor stand 1. The frame or chassis 2 has anupper and lower track 3 and 4 to which the carriage and clamp assembly 5is attached, so as to be movable by means of pinion 6 and rack 7 backand forth along the entire length of chassis 2, so as to bring thebivalve 8 into contact with the diamond cutting blade 9 and the combinedspreader of the shells and knife unit 10, and thereafter the empty shellrelease mechanism 1 1. Conveyor belt 12 receives the empty shell ofbivalve 8. Water spray nozzle 13, shell scrap bin 14, shell scrapdeflector 15, blade motor 16, and belt 17 are also shown.

FIG. 3a through g shows the sequence of operations 4 from the front ofthe machine where the bivalve 8, an oyster with hinge uppermost andbottom shell of oyster toward the right and top shell on the left, isplaced in bivalve carriage and clamp assembly 5 until the empty shellsare released therefrom.

In FIG. 3a each of the two clamps, shown in fully open position, havepointed spring-loaded compressible spikes 19 perpendicular to the face20 of the clamp 18. Spikes 19 are fully extended and bivalve 8 ispositioned between clamps .18 but is not in contact with spikes 19.

In FIG. 3b clamps 18 are in fully closed position, and bivalve 8 isimmovably held by compressed spikes 19.

In FIG. 30 carriage and clamp assembly 5, immovably holding bivalve 8,is advancing toward blade 9 which rotates either clockwise oranti-clockwise.

In FIG. 3d carriage and clamp assembly 5 has advanced beyond blade 9,and bivalve 8 with hinge removed is positioned under shell spreader andknife unit 10, which is in upper position. Dotted lines show spreaderfeet in lower position with spreader closed. Clamps 18 are semiopen,feet of spreaders and partially compressed spikes 19 loosely holdbivalve 8. Knives are sheathed within sleeve 26,

In FIG. 3e shell spreader and knife unit 10 is in lower position,spreader feet 22 are inserted in bivalve 8 approximately five-sixteenthsof an inch, forcing apart at their tops shells 23 and 24 of bivalve 8.Spikes 19 are either partially compressed or partially extended toconform with contours of shells 23 and 24 as so forced apart. Knives 25remain sheathed in sleeve 26.

In FIG. 3] knives 25 are in extended position, passing between spreaderfeet 22, are flexed apart from each other, and have severed the musclesholding meat 27 to shells 23 and 24. The bottoms of shells 23 and 24 areheld apart by flexed knives 25 which extend just beyond the lowermostportion of the shells 23 and 24. Spikes 19 are individually compressedin conformation to contours of shells 23 and 24 as held apart at theirtops by spreader feet 22 and at their bottoms by knives 25. Meat 27 isshown dropping from its shells.

In FIG. 3g carriage and clamp assembly 5 has advanced to the finalposition. Clamps 18 are again fully open, and empty shells 23 and 24 arereleased and fall from carriage and clamp assembly 5.

SHELL SPREADER AND KNIFE MECHANISM FIG. 4 shows oscillating knife shaftmechanism, with oscillating electric motor 28 turning crank wheel 29,connected by crank pin 30 to connecting rod 31. Rod 31 connects to arm32 attached to oscillating knife shaft 33. Shaft 33 is movablevertically by knife shaft handle 34, acting through Scotch yoke device35 attached to hearing block 36. Spreader handle 37 by shaft 38 movescam 39 acting on roller 41 forcing sleeve assembly 42 and knife shaft 33moving by tracks 48 to descend approximately fivesixteenths of an inch,positioning spreader feet into the opening in the bivalve as shown inFIG. 3d.

In FIG. 5 sleeve assembly 42 is shown in upper position with dottedlines to indicate lower position shown in FIG. 4. Further depression ofspreader handle 37 after sleeve assembly is lowered further turns shaft38 rotating cam which acts on roller 43 forcing wedges 44 to slidedownwardly in grooves 49 acting on rollers 45 to compress spreader arms46 pivoting at 47 forcing apart spreader feet 22 forcing open bivalve 8as shown in FIG. 3e and FIG. 6.

In FIG. 6 sleeve assembly 42 is in the lower position, spreader feet 22are apart. Knife shaft 33 has been lowered through sleeve 42 bymechanism shown in top portion of FIG. 4. Knives 25 having spring steelhafts 50 have passed between spreader feet 22 are sprung apart as isalso shown in FIG. 3].

In FIG. 7 the knife assembly is shown with dotted lines illustratingknives 25 apart when spring steel hafts 50 are not compressed together.Adapter 53 is connected to the bottom of knife, shaft 33, which fitsinto the bottom of shaft 33 and is held fast by set screw 52. Pin 51 andadapter 53 are of one-piece construction and are together referred to asthe adaptor. Screws 54 and 55 hold the tops of knife hafts 50 in adapter53. In FIG. 7 adapter 53 is free to slide vertically within sleeve 42.Knives 25 and hafts 50 are one-piece construction, the knives beingapproximately spade-shaped. FIG. shows knife blade 25 with surface 56larger than surface 57.

FIG. 11 shows a modification of the knife shown in FIG. 7. The blades25, lower portions of hafts 50, and the pin portion 51 or adapter 53 arethe same as shown in FIG. 7. A pin 96 having a wedge-shaped lower end isslidably fitted into the lower end of adapter 53. A spiral spring 97fits around pin 96 and butts at its upper end against this lower end ofadapter 53 which serves as a boss, and butts at its lower end against asecond boss 98 formed by the widened diameter of the lower part of pin96. Upper end of hafts 50 fit together to form a V-shaped cleft 99,which receives the wedge shaped end of pin 96. Hafts 50 are attached toadapter 53 by screw 100 which also acts as a fulcrum for the hafts 50.Screw 101 also holds hafts 50 in adapter 53, but by means of slots 102.The upper parts of hafts 50 are free to move within sleeve 42 to theextent permitted by the length of slot 102. Thus knive blades 25 may bedeflected to a limited extent with screw 100 as the center of rotation.

CARRIAGE AND CLAMP ASSEMBLY In FIG. 8 carriage and clamp assembly 5 isshown in detail. Assembly 5 is movable horizontally along tracks 3 and 4by means of pinion 6 attached to shaft 56, which engages rack 7. Shaft56 is turned by hand wheel 57. Handle 58 is fixed to shaft 59 by pin 60.Cam followers 61 and 62 are fixed to shaft 59 by pin 63. A disk offriction belting material 64 is firmly affixed to the vertical face ofthe handle hub 65 of handle 58 and makes frictional contact with theopposing vertical face of hub 66. Handle hub 65 is urged against hub 66by spring 66a and is held in optional positions by frictional contactbetween friction disk 64 and hub 66. Cams 67 and 68 are slidablyattached to shaft 59 and to clamps 18. Spring 69 surrounding shaft 59push cams 67 and 68 apart. Springs 69 are separated by two collars 70.The operation of handle 58 rotates cam followers 63 causing clamps 18 tomove toward or away from each other to grasp or release bivalve 8 bymeans of spikes 19.

FIG. 9 shows the face 71 or clamp 18 perforated by compressible spikes19, spiral springs 72 surrounding the enclosed portion of spikes 19,butting against the interior surface of clamp face 71 and against theinterior surface of back face 73 of clamp 18. The ends of spikes 19protrude through back face 73 of clamps 18 which acts as a guide forspikes 19.

FIGS. 12 and 13 show feeder assembly 104 plunger rod 73 penetrating andslidably supported by hearing block 74. Spring 75 surrounding plungerrod 73 butts against hearing block 74 and collar 76 forcing V-shapedclamp 77 fixed to the end of rod 73 into engagement with bivalve 8forcing the opposite edge of the shell of bivalve 8 into backstop 78.The bottom of bivalve recesses into V-shaped depression 79 in base plate80. Plunger rod 73 has knob 81 attached to end. Feeder assembly 104 isin fixed position and does not move with carriage and clamp assembly 5.

PHYSICAL FEATURES OF BIVALVE UTILIZED BY INVENTION FIG. 14 shows atypical American oyster (Cnassostrea Virginica Gamelin) with largecup-shaped bottom shell 82 smaller flatter top shell 83, narrow thickhinged end 84, and wider and thinner opposite end 85.

FIG. shows the same oyster shown in FIG. 14 as opened, with bottom shell82 at left and top shell 83 at right both resting on their exteriorsurface with hinged 6 end toward bottom of sheet, and with shellsdivided in quadrants. Hinge 85 and hinge ligament 86 are shown on topand bottom portion of the shells. The scars 87 where the single adductormuscle was attached is seen to be in the upper right quadrant of bottomshell 82 and in upper left quadrant of top shell 83.

FIG. 16 represents the bottom shell 82 with hinged end 84 toward top ofsheet. Dotted lines indicated the position normally occupied by the meatof the oyster when its hinged end is held uppermost prior to the openingof the oyster. Dotted lines also indicate the approximate lower positionoccupied by oyster meat after the fluid which normally surrounds themeat its eliminated.

FIG. 17 is the section taken through line 1717 of FIG. 16 showing thecontour of body cavity 88 of oyster after hinged end has been cut offalong that line.

FIG. 18 shows the bottom portion 89 and top portion 90 of a typicalclam, indicating the point of attachment of each of the two separateadductor muscles as marked by scars 91 and 92. The hinge 93 and hingeligament 94 are shown as well as the dotted cutting line 95, which showsthe portion of the shells which are removed when the invention ispracticed.

AUTOMATED MACHINE FIG. 19 shows a Geneva mechanism having turntable 103which successively carries bivalve 8, after it is positioned in clamps18 by feeder assembly 104, to cutting blade 9, shell spreader and knifeunit 10, and finally to shell release mechanism 105. Electric motor 106by conventional mechanism rotates turntable 103. Air cylinder 107 pushesV-clamp 77 inwardly until bivalve 8 is posi tioned against backstop 78.Air cylinder 108 raises feeder assembly 104 until bivalve 8 touchesoverhead stop 109. Air cylinder 109a pushes upwardly on shaft 110 and byrack and pinion mechanism 111 fully closes clamps 18 on bivalve 8. Aircylinder 112 pushes upwardly on shaft 113 and moves clamps 18 tosemi-open position when bivalve 8 reaches a position directly beneathshell spreader-knife assembly 10. Air cylinder 114 lowers knife shaft 33when knife has access to adductor muscles of bivalve 8. Turntable 103next moves clamps 18 holding now empty bivalve shells to shell releasemechanism 105 where air cylinder 115 pushes upwardly rod 116, which, bymeans of rack and pinion mechanism 111, brings clamps 18 to fully openposition, thereby discharging empty shells.

DESCRIPTION OF THE PREFERRED EMBODIMENTS While emphasis will be placedupon the shucking of the American oyster found along the Atlantic andGulf Coasts, and clams, the invention will also shuck the Japaneseoyster Crassostrea gigas, now being grown along the Canadian and NorthPacific Coast of the United States.

In oyster beds the oyster rests upon its large thick cupshaped bottomshell, and the thinner, smaller and flatter top shell is attached to thebottom portion at the beak, or end, by a hinge having a tough ligament.The top and bottom valves or shells are also held together by theadductor muscle, the only attachment between the oyster meat or body andthe shells. This soft, but very strong muscle, holds the two valves in avery slightly parted position while feeding, or in closed water-tightengagement when the oyster is disturbed. In FIG. 15 the scars indicatethe points of attachment of the adductor muscle to the shell interior.Thus, if the oyster is held bottom side down in ones hand with the beakend facing ones wrist, the adductor muscle is always found to beattached at the right quadrant of the circular end of the shell.

While cutting off the hinged end of the oyster leaves the two valveswhich comprise the shell attached only by the adductor muscle, it is notpossible to remove more than from one-half to three-quarters of an inchof shell at the beak without cutting into and damaging the portion ofthe meat which lies close to the hinge. The aperture which is made bysuch a shallow cut is very small. If, however, the free fluid which isnormally entrapped within the bivalve cavity is removed before theshells are cut, the meat no longer floats nor is it suspended in thecavity, but sags into the part of the shells which is lowermost,providing an additional one-half to three-quarters of an inch ofunoccupied space in the shell cavity below the hinge. In practicing theinvention the oyster is forced to release this fluid before the hinge isremoved and a much larger portion of the hinged end is cut away withoutdamage to the meat. A very large opening providing accessibility to theattachment points of the adductor muscle or muscles is thereby provided.

As already stated, the prior art teaches many methods of shocking whichwill cause an oyster to open sufficiently to release the liquidcontained in the shell cavity. As the oyster is frequently covered withmud, sand, etc., and requires washing prior to shucking, and as oystersare sometimes attached together in clusters of two or more or havebarnacles or other sea growth on shells, a washershocker may be employedto (a) wash away foreign matter from the shell exterior, (b) break theconnections between the individual oysters, and (c) shock the oystersufficiently to cause the release of entrapped fluid from its interiorcavity. A rotary washer, preferably having six sides, may be readilyadapted to perform these preliminary operations.

By attaching longitudinal vanes or baffles to the interior of such awasher having the input end slightly higher than the discharge end, theoysters may be fed into the higher end, picked up and dropped repeatedlyby the baffles as they progress toward the discharge end, while beingsprayed with water. The repeated dropping during the washing processseparates most of the attached oysters and sea growths and so stunstheir nervous systems as to relax the adductor muscles, causing theshells to part very slightly at the rounded ends and give up the fluidwithin their shell cavities. As the partial opening of the oyster isinduced only after considerable tumbling, there is ample time for allforeign matter to be washed from the shells before this opening occurs.This treatment does not injure the meats as they are held in liquidsuspension until the shells are slightly parted as described. Afterbeing processed in this manner, the clean oysters may be processed inaccordance with the invention which will now be described.

THE FEEDER ASSEMBLY-STATION l The oyster is placed by hand into thefeeder assembly, hinged and uppermost, cup or bottom of shell facing theright-hand side of the machine, and with the edge of the oysterperpendicular to the tracks on which the carriage and clamp assemblytravels. The thin rounded end of the shell is fitted into the V-shapedrecess in the base of the feeder and the spring-loaded plunger rod withV-shaped clamp engages the edge of the shell facing the operator andforces the opposite edge firmly against the backstop of the feeder. Theoyster is now correctly positioned in the feeder assembly, and thefeeder assembly is raised vertically until the beak of the oyster, whichis uppermost, touches the stop. This stop, which is adjustable,determines how far the shell will be raised above the clamps of thecarriage and clamp assembly, and therefore, how much of the shell willbe cut away by the blade. The oyster is now in the correct position toinsure that the maximum portion of the hinged end will be removedwithout injury to the meat and that the angle of the cut will be such asto provide an opening which affords the most direct knife path to thepoints of attachment of the adductor muscle.

With the oyster now correctly oriented between the open clamp of thecarriage and clamp assembly, the cam handle is next moved to the closedposition, causing the oyster to be held fast by the compressiblespring-loaded spikes, which compress in conformity to the irregular andnon-uniform contour of each individual oyster, and which 8 project atright angles from the two parallel clamp faces. The plunger rod of thefeeder assembly is next withdrawn by the operator so that it is out ofcontact with the oyster and the feeder assembly is returned to its lowerposition, leaving the oyster now securely held between the spikes of theclamps of the carriage and clamp assembly.

SHELL CUTTING OPERATION-STATION 2 The carriage and clamp assemblycontaining the oyster is moved along the tracks vertically to the leftby the rack and pinion mechanism, which is activated by the handwhecl,and is thus brought in contact with the diamond edge cutting blade whichis so positioned in relation to the tracks as to cut in a horizontalplane about threeeighths of an inch above the top of the clamps. Theelectrically driven 12-inch blade revolves either clockwise orcounter-clockwise at 1,750 rpm. and is cooled and cleansed by a jet ofcold water which sprays the top and bottom of the blade at the point ofcontact with the oyster. Rubber wipers on the top and bottom of theblade collect and drain away the water from the machine. Because of thenecessity of cutting the shell quickly to accelerate production, theoyster is advanced rapidly through the cutting zone.

As the liquid has been removed from the oyster cavity during thewashing-shocking process the meat of the oyster no longer occupies thetop portion thereof, permitting the cutting away of the hinge and aconsiderable portion of the shells below the hinge. The portion of theshells which is removed is intercepted by the rubber wipers describedabove which guide this portion to a waste receptacle. The angle of thecut produces a large opening at a location which provides excellentaccess to the quadrants of the shells to which the adductor muscles areattached.

SPREADING OF SHELLS AND ADDUCTOR MUSCLE CUTTINGSTATION 3 After passingthrough the shell cutting zone, the carriage and clamp assembly, holdingthe oyster with hinge end removed, is moved to the left by the operationof the handwheel and is stopped when its center is directly beneath thecenter of the combined shell spreader and knife unit. The cam handle isthen moved upwardly to a position midway between the open and closedpositions so that the oyster shell is no longer held completely rigidbetween the now semi-relaxed spikes of the clamps. The spreader handleis then depressed rotating, two cams which perform two successivefunctions. The first cam acts upon and lowers about five-sixteenths ofan inch a sleeve to which the shell spreader is attached. The shellspreader consists of a pair of arms which pivot on the sleeve andterminates in spreader feet. The lowering of the sleeve and attachedspreader places the two spreader feet, which are initially closetogether, within the aperture of the oyster shell made by the cuttingblade. After the sleeve with attached spreader is lowered, the secondcam, which is on the same shaft, acting upon a roller at the top of aV-shaped wedge, causes the wedge to move downward ly in its verticaltracks and to engage rollers on the ends of the spreader arms oppositethe spreader feet. The downward movement of the wedge against theserollers forces apart the spreader feet and with them the two portions ofthe shells, thereby widening the opening by about one and one-quarterinch. As explained earlier, the semi-open position of the clamps of thecarriage and clamp assembly and compressibility of the spikes allow alimited lateral separation of the top portions of the shells which isnot possible when the clamps are in the closed position. The use of thespreader is not required when only large oysters or clams are beingshucked.

After the opening between the shells is enlarged as described, the knifeshaft handle is depressed. This handle is attached by a shaft and yokearrangement to the knife shaft, a rod which is slidably fitted into thetop of the sleeve on which the spreader arms are attached. Within thesleeve the knife shaft is coupled to the two knife hafts which aremounted in tweezer-like relationship. The hafts of these knives are heldtightly together at their tops by set screws which hold them into anadapter by which they are linked to the knife shaft. The hafts are ofspring steel so shaped as to be separated from each other at theirbottoms but converging at their tops like an inverted V. A knife bladeis formed at the botom of each haft as an integrel part thereof. Thisnearly spadeshaped blade is slightly concave and its leading edges arerelieved to facilitate sliding engagement with the internal walls of theshell cavity.

A pantograph knife as shown in FIG. 11 may be used for bivalves havingunusually irregular interior shell configurations. The blades of thisversion are movable toward and away from each other in tweezer fashionin the manner already described and either will also deflect sideways aswell to conform to interior shell contour while being inserted into thebivalve shell cavity.

Prior to the depression of the knife shaft handle the hafts arecompletely sheathed within the sleeve, and are compressed together inclose relationship throughout their entire length. The blades are notsheathed but are positioned just outside of the lower end of the sleeveand above the spreader feet. Depression of the lever expels the haftsfrom the sleeve, and the blades remain together until they pass betweenthe open spreader feet and into the expanded opening in the shell as thebowed hafts emerge from the sleeve they spring apart causing the knifeblades to separate with considerable pressure against the opposinginterior walls of the shell cavity. The knives are so shaped and theoyster is held in such a position by the clamps of the carriage andclamps assembly that the blades follow the contours of the inner shellsurfaces to the precise points where the adductor muscle is attached.The knives sever the muscle at both points of attachment and then,continuing to follow the contours of the shell, penetrate deeper intothe cavity and ultimately emerge below the lowest edge of the shells.The pressure of the spring hafts upon the blades in the lower part ofthe oyster cavity forces the shells apart at their bottoms and the meatof the oyster drops out of the shells into a container.

The hafts and blades are next quickly withdrawn from the shells byraising the knife shaft lever. This, of course, causes the hafts to besheathed in the sleeve, and the spreader feet to come together and to bewithdrawn from the now empty shells. The withdrawal of the knife andspreader from the interior of the shells causes the two shells to bebrought together again by the pressure exerted by the spring-loadedspikes against the exterior surface of the shells. As thus held theshells are ready to be carried by the carriage and clamp assembly whenit is moved to the left to the shell release station.

SHELL RELEASE-STATION 4 The carriage and clamp assembly is next advancedto the final station by further rotation of the handwheel, and isbrought to rest over the container or conveyor which receives emptyshells. The cam handle is then raised to the open position causing theclamps to open fully and release the shells, which fall into a containeror conveyor. The carriage and clamp assembly is returned to station 1and the process is completed.

SIMULTANEOUS OPERATION OF ALL FOUR STATIONS Because stations two, threeand four can only operate in cooperation with the carriage and clampassembly which holds the bivalve while it is being processed at thesestations, production may be greatly increased by increasing the numberof such assemblies so that each station may be operated simultaneously.This, of course, will make it possible for the cutting of the shell, theslowest of the successive steps, to be carried out almost continuously.It is also possible by the use of more than one blade in conjunctionwith a plurality of carriage and clamp assemblies 10 to increaseproduction to meet almost any demand, since the operations at stationsthree and four are performed in stantaneously.

THE SHUCKING OF CLAMS The process and apparatus described may beemployed with minor modifications in the shucking of raw clams. Theprincipal difference between the problem encountered in shucking oystersand clams is that the latter has two adductor muscles rather than one.The location of these muscles is shown in FIG. 18. While there aredifferent positions in which clams may be held in the clamps to practicethe invention, the preferred method is to place uppermost the portion ofthe shell which contains the hinge as is done with oysters. This willresult in a blade cut as indicated by the dotted line in FIG. 18, whichremoves both the hinge 93 and hinge ligament 94. After this blade outhas been made the shells are held together by two muscles instead of oneas in an oyster. In order that the knife will reach and sever both endsof each of the two adductor muscles the knife is made to oscillate in asemi-circular orbit by a mechanism, to be described, as it is loweredinto the interior of the clam cavity.

OSCILLATING KNIFE By the use of mechanism such as shown in FIG. 4 theknife blades may be caused to oscillate within the clam cavity by apartial rotation and counterrotation of the knife shaft. The arc ofrotation of the blades within the cavity must be sufficient to insurethat the blades contact the entire length of the cavity in eachdirection. This produces a broad knife path and is particularly suitablefor use when shucking clams.

PARTIAL SHUCKINGS O-F BIVALVES The invention will also produces oystersor clams on the half shell when a knife having but a single blade isused at Station 3. This variation removes only one shell leaving themeat attached to the other shell. When so modified ready to servebivalves are produced which may be marketed fresh or after freezing.

We claim:

1. An apparatus for shucking bivalves comprising means for holding in anupright position the bivalve shells means for making an opening in saidshells by removing the portions thereof which are held uppermost; meansfor insertion through said opening for severing the adductor muscle ormuscles of said bivalve where attached to said shells, and for forcingapart the bottom portions of said shells sufficiently to allow saidedible portion to drop clear of said shells between the bottom portions;and carrier means for moving said bivalve holding means in a path inwhich the bivalve is brought into engagement with said means for makingsaid opening, and with said means for severing said adductor muscle,said carrier means holding the bivalve in such upright positionthroughout said path.

2. An apparatus for shucking bivalves as in claim 1, having means forpenetrating and widening the said opening made in said shells, whilesaid bivalve is stationed directly beneath said means for severing saidadductor muscle or muscles.

3. An apparatus for shucking bivalves as in claim 1, wherein saidcarrier means is a Geneva mechanism.

4. An apparatus for shucking bivalves as in claim 1, which includespneumatic means for operating: (a) the means for placing and holding thebivalve in a selected position, and for releasing shells, (b) means forsevering adductor muscles and for forcing apart the bottom portions ofshells.

5. An apparatus for shucking bivalves as in claim 1, having a pluralityof said means for holding bivalves and/ or said means for making anopening in the shell.

6. An apparatus for shucking bivalves as in claim 1, wherein the meansfor holding bivalves is a clamp containing resilient spikes by whichsaid bivalve is held op- 1 1 tionally either immovably when said clampsare fully closed or flexibly when said clamps are intermediate theirfully open and fully closed positions.

7. An apparatus for shucking bivalves as in claim 1, wherein said meansfor severing the adductor muscle is a pair of knives which oscillate inan arc while in contact with the interior of the shell cavity of saidbivalve, which arc conforms to the contours of said interior of saidshell cavity.

8. An apparatus for shucking bivalves comprising means for holding abivalve in a position with its hinge at the top, means at one stationfor removing the topmost portion of the bivalve while held by saidholding means to provide a hole in the top, means at a later stationmovable into said hole to sever at least any adductor muscle on one ofthe shells of the bivalve, and means to move the bivalve from the onestation to the later station.

9. An apparatus as claimed in claim 8 further including stationary meansat said later station engageable in said opening and operable before theoperation of said severing means to spread apart the halves of the shelladjacent said opening.

10. An apparatus as claimed in claim 9 in which said bivalve is held atsaid later station with the hole directed upwardly and said severingmeans includes means to sever the adductor muscles on both shells andfor forcing apart the bottom portions of said shells, whereby the meatcan drop out between said parted bottom portions.

11. In an apparatus for shucking bivalves, means for opening a pair ofshells having the hinge portion removed therefrom to provide a hole inthe shells and to remove the edible portion of the bivalve from suchshells, comprising means to hold the bivalve with the hole upwardlydirected, members mounted to enter the hole while the bivalve is so heldand engage the inside of each of the shells on opposite sides of theedges of the hole, means to move said members apart to enlarge the hole,and means enterable into the enlarged hole while the bivalve is so heldfor first severing the adductor muscles and then spreading apart thelower ends of the shells, whereby the meat can drop out between theparted lower ends.

12. In an apparatus as claimed in claim 11, said severing and spreadingmeans including a pair of knives, means mounting the knives for downwardmovement into the bivalve through said hole, said mounting means causingthe lower end portions of the knives to remain close together until theyhave passed between said members and thereafter to spread apart againstthe interior of the walls of the bivalve where the adductor muscles arelocated.

13. In an apparatus for shucking bivalves having the hinge portionremoved therefrom to provide a hole in the shells, means for holding thebivalve with the hole uppermost, means for moving the bivalves whileheld by said holding means in a path, stationary means operable on thebivalve while so held in said paths for severing the adductor musclescomprising a pair of resilient knives having their lower ends urgedapart, means mounting the knives for movement into the shell throughsaid hole, said mounting means causing the lower ends of the knives toremain close together until they have passed through the hole andthereafter to spread apart against the inside of the parts of the wallsof the bivalve where the adductor muscles are located to sever theadductor muscles.

14. Apparatus for shucking bivalves comprising means to grip a bivalvein an upright position, means to move the 12 bivalve so gripped in asubstantially horizontal path, means engageable with a bivalve in suchpath to cut off the upper parts of the shells of the bivalve, andstationary means adjacent a later portion of the path for removing themeat from the bivalve.

15. Apparatus as claimed in claim 14, said removing means comprisingmeans enterable into the hole for severing the adductor musclesincluding a pair of knives, and means mounting the knives for downwardmovement into the bivalve through said hole, said mounting means causingthe lower end portions of the knives to remain close together until theyhave passed between said members and thereafter to spread apart againstthe interior of the walls of the bivalve where the adductor muscles arelocated.

16. Apparatus as claimed in claim 14, including means to hold thebivalve in a position with its cut-off top upwardly directed while it isoperated on by said removing means.

17. In apparatus for shucking bivalves having a hole cut in the topthereof, means for holding the bivalve in upright position with the holeuppermost, and means enterable into the hole for severing the adductormuscles including a pair of knives, and means mounting the knives fordownward movement into the bivalve through said hole, said mountingmeans causing the lower end portions of the knives to remain closetogether until they have passed between said members and thereafter tospread apart against the interior of the walls of the bivalve where theadductor muscles are located.

18. In apparatus for shucking bivalves having a hole cut in the topthereof, means for holding the bivalve in upright position with the holeuppermost, and means enterable into the hole for severing the adductormuscles and for thereafter spreading apart the lower ends of the shells,whereby the meat can drop out between the parted lower ends.

19. In a machine for shucking bivalves, means to hold a bivalve having ahole in its top in upright position, and adductor muscle severing meanscomprising a pair of knives with elongated stems and blades at the lowerends of the stems, guide means holding said knives normally with theirstems close together and substantially parallel to each other, saidstems being of resilient material and being tensioned to tend to spreadaway from each other at their lower ends, said guide means permittingdownward movement of the knives and including means to hold the bladessubstantially together until they have entered the hole and thereafterto permit the blades to spread apart against the inner walls of theshells.

References Cited UNITED STATES PATENTS 848,784 4/1907 Torsch et al. 17-74 2,808,613 10/1957 Palmere 1776 3,206,797 9/1965 Smith, Jr 17-743,239,877 3/1966 Lapeyre et al. 17-74 3,303,527 2/1967 Lanier 17-74LUCIE H. LAUDENSLAGER, Primary Examiner U.S. Cl. X.R. 17-48

